In the U.S. alone approximately one million women will have breast biopsies because of irregular mammograms and palpable abnormalities. See FIG. 1 which diagrams the current treatment algorithm for non-palpable breast lesions. Biopsies can be done in a number of different ways for non-palpable lesions, including surgical excisional biopsies and stereotactic and ultrasound guided needle breast biopsies. In the case of image directed biopsy, the radiologist or other physician takes a small sample of the irregular tissue for laboratory analysis. If the biopsy proves to be malignant, additional surgery (typically a lumpectomy or a mastectomy) is required. The patient then returns to the radiologist a day or two later where the biopsy site (the site of the lesion) is relocated by method called needle localization, a preoperative localization in preparation for the surgery.
Locating the previously biopsied area after surgical excision type of biopsy is usually not a problem because of the deformity caused by the surgery. However, if the biopsy had been done with an image directed needle technique, as is common, help in relocating the biopsy site is usually needed. One procedure to permit the biopsy site to be relocated by the radiologist during preoperative localization is to leave some of the suspicious calcifications; this has its drawbacks.
Another way to help the radiologist relocate the biopsy site involves the use of a small metallic surgical clip, such as those made by Biopsys. The metallic clip can be deployed through the biopsy needle, and is left at the biopsy site at the time of the original biopsy. With the metallic clip as a guide, the radiologist typically inserts a barbed or hooked wire, such as the Hawkins, Kopans, Homer, Sadowski, and other needles, back into the patient""s breast and positions the tip of the wire at the biopsy site using mammography to document the placement. The patient is then taken to the operating room with the needle apparatus sticking out of the patient""s breast. While the clip provides a good indication of the biopsy site to the radiologist during preoperative localization, the clip remains permanently within the 80% of patients with benign diagnoses. Also, because the clip is necessarily attached to a single position at the periphery of the biopsy site, rather than the center of the biopsy site, its location may provide a misleading indication of the location of diseased tissue during any subsequent medical intervention. In addition, the soft nature of breast tissue permits the tip of the barbed or hooked needle to be relatively easily dislodged from the biopsy site. The clip is also relatively expensive.
Another localization method involves the use of laser light from the tip of a optical fiber connected to a laser. A pair of hooks at the tip of the optical fiber secures the tip at the biopsy site; the glow indicates the position of the tip through several centimeters of breast tissue. This procedure suffers from some of the same problems associated with the use of barbed or hooked wires. Another preoperative localization procedure injects medical-grade powdered carbon suspension from the lesion to the skin surface. This procedure also has certain problems, including the creation of discontinuities along the carbon trail.
The present invention is directed to a biopsy localization method and device which uses a locatable bioabsorbable element left at the biopsy site so that if testing of the biopsy sample indicates a need to do so, the biopsy site can be relocated by finding the bioabsorbable element. This eliminates the need to use of metallic clips during biopsies and often eliminates the need for a return to the radiologist for pre-operative needle localization. In addition, the bioabsorbable element can be used as a therapeutic tool for treatment of the diseased lesion and for hemostasis.
A biopsy localization device made according to the invention includes a bioabsorbable element delivered in a pre-delivery state to a soft tissue biopsy site of a patient by an element delivery device. The bioabsorbable element may be palpably harder than the surrounding soft tissue at the biopsy site when in the post-delivery state.
One preferred material used as the bioabsorbable element is a dehydrated collagen plug. This type of plug may swell and is palpable for subsequent location by the surgeon. The collagen plug may not swell at all. In some situations, such as with small breasted women or where the biopsy site is close to the surface, a non-swellable bioabsorbable material, such as a round pellet of PGA, can be used instead of a swellable bioabsorbable material. The bioabsorbable material can also be made so that it is absorbed quickly to produce a local tissue inflammation; such a localized inflammation can be used to locate the biopsy site instead of location by palpation. Instead of leaving, for example, a collagen plug, a PGA pellet or a bioabsorbable suture material at the biopsy site for location by palpation or inflammation, a length of bioabsorbable suture material, a collagen filament, or other bioabsorbable material extending from the biopsy site out through the skin can be used. In this case the surgeon can follow the bioabsorbable suture material to the biopsy site in a manner similar to that used with Hawkins needles. In other cases, such as in the case of a deeply located lesion or large breast, the bioabsorbable material may need to be located by the radiologist, by for example, ultrasound or mammography. In any event the bioabsorbable material will typically be absorbed within about a month of placement. The invention thus eliminates the use of metal clips during biopsies and usually eliminates the need for return to the radiologist for preoperative localization.
While the primary use of the device is intended to localize the site of needle biopsies for possible future surgical excision, the device may also be useful in marking the site of surgical excisional biopsies. For example, during a wide surgical excision for cancer diagnosed by a recent surgical excisional biopsy, surgeons frequently have difficulty in determining the precise relationship of the previously excised tissue to the surgical wound. Therefore, more tissue is removed than might have been removed had the exact location of the previous lesion been more definite. With the present invention, a bioabsorbable element may be inserted into the biopsy site during a surgical excisional biopsy before the wound is closed to mark the site for potential wide excision should the biopsy reveal cancer. Alternatively, a bioabsorbable element may be placed at the biopsy site using a delivery device by partially or completely closing the wound and then depositing the bioabsorbable element through the delivery device and removing the delivery device through the closed incision. The presence of the palpable marker within the previous excisional biopsy site would allow the surgeon to more easily and confidently remove tissue around this site, and preserve more normal breast tissue.
Another use of the device is to primarily localize a non-palpable lesion prior to surgical excisional biopsy. Instead of using the needle/wire apparatus which has a tendency to migrate and become dislodged with traction, the palpable marker may be inserted into the suspicious area of the breast under mammographic or ultrasonic guidance immediately prior to the surgical excisional biopsy. This would provide a palpable locator for the surgeon as described above. In this instance, the marker would only need to be palpable, and not necessarily bioresorbable, since the intent would be to remove it in all cases.
In addition to permitting the biopsy site to be located by subsequent palpation or other means, the invention also can provide hemostasis and therapeutic benefits. Since the bioabsorbability can be varied from a day or two to a year or more, the material may be used to treat the diseased tissue and not just locate it. Some current therapies include radiation, chemotherapy, gene therapy as well as other technologies and therapies. Because the bioabsorbability can be easily varied, a medium can be place into the bioabsorbable element and be externally excited or triggered in those cases where the biopsy results are malignant. Further, the bioabsorbability concept can be used for future implantation of a therapeutic agent. For example, if the bioabsorbable element is a dehydrated collagen, this material could be used as a reservoir for, for example, delivery of materials that effect chemotherapy, brachytherapy, etc. Once the laboratory results are received and show the biopsy is malignant and therapy is required, by surgical excision or otherwise, the physician may inject, for example, a radiation pellet, a chemotherapeutic agent or a gene therapeutic agent into or adjacent to the bioabsorbable element for direct treatment of the diseased tissue.
The change in the bioabsorbable element can be via one of several ways, such as hydration or desiccation, change in temperature, electrical stimulation, magnetic stimulation, chemical or physical reaction with another material, additives, enzymatic reactions, ionization, electrical charges, absorption, as well as other means. The invention may employ one or more of these techniques or measures or others, to change the consistency, hardness and or size of the bioabsorbable element between its deployed and non-deployed states. The visual detectability of the bioabsorbable element may be aided by the use of a coloring agent, such as methylene blue or some other dye. The radiographic detectability of the element may be enhanced by a radiopaque marker. As well, ultrasonic detectability may be enhance by special treatment of the bioresorbable element.
The bioresorbable element may have margins which are roughened so as to prevent migration within the tissues. Filaments extending from the margins of the bioresorbable element may be utilized also to stabilize the position of the device within the cavity. The filaments may or may not be composed of the same material as the bioresorbable element.
The provision of hemostasis helps to lessen the bleeding and swelling within and about the biopsy site. This can be accomplished by physical or chemical means. That is, the device may swell so that it essential fills the biopsy cavity or the device may have a chemical reaction with blood or blood products to cause effective blood clotting, or both. Other methods for causing local hemostasis are also possible with the invention.